The density functional theory (DFT) calculations were performed with the VASP [1]}, [2]} code using the projector augmented wave (PAW) method [3]}. We chose the PBEsol [4]}, [5]}, [6]} exchange-correlation functional, which is known to improve the structural description of solids as compared to PBE [7]}. The following valence electron configuration was used: 4\(s^{1}\) 3\(d^{8}\)  for Co, 6\(s^{1}\) 5\(d^{8}\)  for Ir, 4\(s^{2}\) 4\(p^{6}\) 5\(s^{2}\)  for Sr and 2\(s^{2}\) 2\(p^{4}\)  for O.
To account for static electronic correlations we included a Hubbard \(U\)  term, using the Dudarev approach [8]}. We summarize here previously used \(U\)  values for related compounds, but note that values applied or obtained with different codes are not directly comparable [9]}, [10]}: \(U_{\rm Co}=\) 5.44 eV and \(U_{\rm Ir}=\) 2.77 eV, \(J_{\rm Co}=\) 0.918 eV and \(J_{\rm Ir}=\) 0.544 eV from  [11]} were chosen in a previous study of SCIO [12]} with the WIEN2k code[13]}. For SCO the values previously used in VASP calculations range from \(U_{\rm Co}=\) 2.5 eV and \(J_{\rm Co}=\) 1.0 eV [14]} to \(U_{\rm Co}=6 eV\)   [15]}. While element specific \(U\)  values in general depend on the local environment and oxidation state [16]}, for consistency and comparability we selected here the same \(U\)  values for the DP and the end members: \(U=3.0\)  eV for the Co ion, in order to describe correctly the FM metallic ground state of bulk SCO, as discussed below, as well as \(U =1.37\)  eV, \(J=0.22\)  eV for Ir, obtained from the constrained random phase approximation with the VASP code for SIO  [17]}. Additional calculations were performed with the Liechtenstein [18]} approach, to ensure that the results of both approaches are consistent. In the following we discuss the ones obtained with the Dudarev approach.
